58 Conservation Department 



condition, if extensive enough to affect their abundance, would be 

 observed in the inspection of thousands of pounds caught yearly by 

 the commercial interests for marketing purposes. Storms may pro- 

 duce mechanical injury to a small percentage of fish in shallow 

 water, one of the principal effects being sand in the gills, which pre- 

 vents the function of breathing, or injury to the issue after remov- 

 ing protective substances, subjecting the fish to bacterial and fun- 

 gus infection. 



3. — Chemical Studies of Lake Erie 

 By Roger C. Williams 



The chemical investigation of Lake Erie was undertaken chiefly 

 for the purpose of ascertaining the amount and extent of pollution 

 from sewage and industrial wastes. Something of the normal 

 chemical conditions in the lake Avas also determined as being of 

 biological significance. 



In order to carr}- out the chemical program the following 

 analyses were made : Determination of free ammonia, albuminoid 

 ammonia, and nitrates, free carbon dioxide, bicarbonate, carbonate, 

 dissolved oxygen, hydrogen ion concentration and temperature. 



Three chemical trips were made on the IT. S. F. S., Shearwater, 

 in July, August and September for the purpose of visiting the 

 stations chosen as representative of that eastern portion of the 

 lake included in the survey. For the exact location of these sta- 

 tions see fig. 1. 



Methods. — For the nitrogen analyses a one-liter sample of 

 water was collected from the middle depth of each station in July, 

 and from both the surface and bottom in August and September. 

 The collection was accomplished by lowering a one-liter glass 

 stoppered bottle in a special frame to the desired depth. It was 

 then filled by working a double tripping device which opened and 

 closed the bottle in situ. The samples were kept in these bottles 

 on ice until analysis could be made in the laboratory. 



Water samples for all other analyses were taken in a Greene- 

 Bigelow water sampler, using proper precautions so as not to 

 change the chemical properties of the water. The titrations for 

 carbon dioxide, oxygen, and the pH determinations were made 

 immediately in the field laboratory on board the Shearwater. 



Wherever analyses were made temperature readings were also 

 taken at the same depths. For this purpose reversing thermom- 

 eters of the Negretti-Zambra and Richter types were used. 



In executing the chemical determinations standard methods were 

 employed as recommended by the American Public Health Associ- 

 ation, '^Standard Methods of Water Analysis" for 1925. 



The answer to the i)roblem of ]iollution in the lake proper may 

 be discussed briefly in the light of the chemical analj^ses. It must 



The City of Buffalo, through the co-operation of Dr Francis E. Fronczak, Health 

 Commissioner, and Dr Charles A. Bentz, Director, Division of Communicabie 

 Diseases Laboratories, contributed the services of the City Chemist and a Bacterio- 

 logist to assist in Lake Erie survey work. 



